Down-draft heating device

ABSTRACT

A heating device includes: a primary burn chamber; a secondary burn chamber; a solid fuel support structure separating the primary burn chamber and the secondary burn chamber, the fuel support structure being operable to support a solid fuel for burning in the primary burn chamber, to pass air from the secondary burn chamber to the primary burn chamber and to pass gas and particulates from the primary burn chamber to the secondary burn chamber; an exhaust port operable to exhaust air; a cooling chamber disposed between the secondary burn chamber and the exhaust port, the cooling chamber being operable to extract heat from gases from the secondary burn chamber; a first port operable to supply external air to the primary burn chamber; a second port operable to supply external air to the secondary burn chamber; and a gas flow controller.

The present application claims priority from U.S. Provisional Application No. 62/063,879 filed Oct. 14, 2014, the entire disclosure of which is incorporated herein by reference.

BACKGROUND

The present invention generally deals solid filet burning stoves. Many conventional solid fuel burning stoves burn such solid fuels as wood, coal, pellets, etc, The solid fuel is placed in a burn chamber and is lit. The fuel burns, heating the stove, which in turn heats the outside air.

Many of these stoves exhaust the heated air through a stack that leads the heated air outside the home. Unfortunately, these conventional stoves are inefficient in that much of the heat escapes with the heated air through the stack, as opposed to heating the outside air around the stove. Further, the exhausts are dirty is that they include many particulates because the temperature of the flame from the burning fuel is insufficient to break down all the particulates.

A down-draft stove provides a second burn, wherein gases are forced down through the solid fuel. This second burn has a much higher temperature than a regular burn in a solid fuel burning stove and drastically decreases the particulates in the exhausted gases. However, a drawback of such down-draft stoves is that the temperature of the secondary burn is so high, that the parts of the stove associated with the second burn deteriorate and degrade over time.

There exists a need to provide a more energy efficient and cleaner burning solid fuel burning stove.

SUMMARY

The present invention provides a more energy efficient and cleaner burning solid fuel burning stove.

Various embodiments described herein are drawn to a device that includes heating device includes: a primary burn chamber; a secondary burn chamber; a solid fuel support structure separating the primary burn chamber and the secondary burn chamber, the solid fuel support structure being operable to support a solid fuel for burning in the primary burn chamber, to pass air from the secondary burn chamber to the primary burn chamber and to pass gas and particulates from the primary burn chamber to the secondary burn chamber; an exhaust port operable to exhaust gases, a cooling chamber disposed between the secondary burn chamber and the exhaust port, the cooling chamber being operable to extract heat from gases from the secondary burn chamber; a first port operable to supply external air to the primary burn chamber; a second port operable to supply external air to the secondary burn chamber; and a gas flow controller operable to block the exhaust port in a downdraft mode thus preventing exhaust gases from exhausting through the exhaust port and operable to unblock the exhaust port in a updraft mode such that exhaust gases exhaust through the exhaust port.

BRIEF SUMMARY OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part of the specification, illustrate an exemplary embodiment of the present invention and, together with the description, serve to explain the principles of the invention. In the drawings:

FIG. 1 illustrates an oblique view of functional components of a down-draft heating device in accordance with aspects of the present invention;

FIG. 2 illustrates another oblique view of separated functional components of the down-draft heating device of FIG. 1;

FIG. 3 illustrates an example heating device bottom of an example down-draft heating device in accordance with aspects of the present invention;

FIG. 4 illustrates an example air input chamber of an example down-draft heating device in accordance with aspects of the present invention;

FIG. 5 illustrates an oblique view of the example air input chamber of FIG. 4 in addition to a rear portion;

FIG. 6 illustrates an oblique view of a more completed down-draft heating device of FIG. 5;

FIG. 7 illustrates an oblique view of a more competed down-draft heating device of FIG. 6;

FIG. 8 illustrates an oblique view of a more competed down-draft heating device of FIG. 7;

FIG. 9 illustrates an oblique view of a more competed down-draft heating device of FIG. 8;

FIG. 10 illustrates an oblique view of a complete down-draft heating device of FIG. 9;

FIG. 11 illustrates air flowing in and gas flowing out of the down-draft heating device of FIG. 10 during an up-draft mode of operation;

FIG. 12 illustrates air flow through the heating device bottom of FIG. 3;

FIG. 13 illustrates air flow through the heating device air input chamber of FIG. 3;

FIG. 14 illustrates air flow through the heating device air input chamber of FIG. 5;

FIG. 14 illustrates up-draft air flow in through the heating device bottom of FIG. 6;

FIG. 15 illustrates gas flow in the primary burn chamber as shown in FIG. 8;

FIG. 16 illustrates gas flow in an up-draft operation of the down-draft heating device as shown in FIG. 9;

FIG. 17 illustrates gas flow in a down-draft operation of the down-draft heating device as shown in FIG. 9;

FIG. 18 illustrates gas flow in a down-draft operation of the down-draft heating device as shown in FIG. 8; and

FIG. 19 illustrates down-draft air flow in through the heating device bottom of FIG. 6.

DETAILED DESCRIPTION

Aspects of the present invention are drawn to a solid fuel down-draft heating device that is switchable between an up-draft mode of operation and a down draft mode of operation,

In the up-draft mode of operation solid fuel burns in a primary burn chamber. External air is supplied from a supply port in the bottom of the heating device. An up-draft exhaust port is uncovered and a down-draft exhaust port may be covered. Air and gas heated from the burning fuel in the primary burn chamber exhaust through the up-draft exhaust port in the top of the burn chamber. A chamber, having the down-draft exhaust port for use in the down-draft mode of operation, holds a portion of air that is continuously heated in the up-draft mode.

In the down-draft mode of operation, the up-draft exhaust port is covered and the down-draft exhaust port is uncovered. The heated air and gas in the chamber having the down-draft exhaust port then exhausts from the heating device, pulling air down through the burning fuel—thus creating a “down draft,” The down draft enables a second burn of recycled air and gases in a secondary burn chamber. The second burn generates a dramatically increased amount of heat than that of the primary burn in the up-draft mode.

A first aspect of the present invention is drawn a secondary burn chamber formed of materials that can withstand high temperatures, such as ceramics and metals covered by ceramics in this manner, the parts forming the secondary burn chamber withstand thermal degradation and destruction over conventional solid fuel down-draft heating devices.

A second aspect of the present invention is drawn to a plurality of exhaust manifolds arranged to conduct heat from surfaces of the secondary burn chamber to the outside air around the down-draft heating device. These exhaust manifolds therefore perform two important tasks. Firstly, the exhaust manifolds more efficiently heat the room surrounding the down-draft heating device because more heat from the secondary burn is transferred to the outside air before the air and gasses are exhausted from the down-draft heating device. Secondly, the exhaust manifolds sink the heat from the surfaces of the secondary burn chamber, thus cooling the surfaces of the secondary burn chamber, and thus preventing thermal degradation and destruction of the surfaces of the secondary burn chamber.

A third aspect of the present invention is drawn to separate openable windows for each of the primary burn chamber and the secondary burn chamber. In this manner, if the window for the secondary burn chamber is opened, while the down-draft heating device is operating in the down-draft mode, the secondary burn in the secondary burn chamber is cease.

A down-draft heating device in accordance with aspects of the present invention will now be described with reference to FIGS. 1-19.

The functional structure of a down-draft heating device in accordance with aspects of the present invention will now be described, with reference to FIGS. 1-2.

FIG. 1 illustrates an oblique view of functional components of a down-draft heating device 100 in accordance with aspects of the present invention.

FIG. 2 illustrates another oblique view of separated functional components of down-draft heating device 100.

As shown in the figure, down-draft heating device 100 includes an exhaust port 202, a primary burn chamber 204, a secondary burn chamber 206, an gas flow controller 208, a solid fuel support structure 210, an air supply channel 212, an air supply channel 214, an exhaust manifold 213, an exhaust manifold 215, a supply air intake 216, an airwash intake 218, an air preheating chamber 220, a cooling chamber 222, a primary burn chamber door 224, a primary burn chamber window 226, a secondary burn chamber door 228 and a secondary burn chamber window 230.

Exhaust port 202 may he any system or structure that exhausts post incineration air and particulates from down-draft heating device 100. It is a goal to render exhaust eases from exhaust port 202 to a temperature that is sufficient to provide buoyant lift to the exhaust gases so as to leave exhaust port 202. In this manner, down-draft heating device 100 would have effectively transferred most heat from the incineration process to the outside air surrounding down-draft heating device 100. It is another goal to minimize particulates within the exhaust from exhaust port 202. In this manner, down-draft heating device 100 would maximize the amount of incinerated solid matter to create heat and ash, which has settled within down-draft heating device 100. In this manner, down-draft heating device 100 would provide a “clean” environment.

Primary burn chamber 204 may be any system or structure that is a chamber for burning solid fuel to create heat in both an up-draft mode and a down-draft modern in the up-draft mode, relative positioning of exhaust ports force heated gases to create a draft in an upwards direction, away from solid fuel support structure 210. In the down-draft mode, relative positioning of exhaust ports force heated air to create a draft in a downwards direction, through solid fuel support structure 210 and into secondary burn chamber 206.

Secondary burn chamber 206 may be any system or structure that is a chamber for providing a secondary incineration of gases and particulates resulting from the burning of the solid fuel in primary burn chamber 204 in the down-draft mode.

Gas now controller 208 may be any system or structure that tray transfers air, gases and particulates originating from primary burn chamber 204 to exhaust port 202 during an updraft mode. Gas flow controller 208 may be any system or structure that transfers air, gases and particulates originating from secondary burn chamber 206 to exhaust port 202 and prevents transfer of air, gases and particulates originating from primary burn chamber 204 to exhaust port 202 during a down-draft mode.

Solid fuel support structure 210 may be any system or structure that that provides support frit solid fuel to burned in prima y burn chamber 204 and that passes air from secondary burn chamber 206 to primary burn chamber 204 in an up-draft mode and passes air, gasses and particulates from primary burn chamber 204 to secondary burn chamber 206 in a down-draft mode. Non-limiting examples of solid fuel support structure 210 include one of the group consisting of a grate, a mesh, a slatted-structure, a screen and combinations thereof. Because of the extremely high temperatures associated with a secondary burn in secondary burn chamber 206, solid fuel support structure 210 should be made of a material that provides sufficient structural support to support a solid fuel, a non-limiting example of which includes wood, and that can withstand high temperatures. Non-limiting examples of materials of solid fuel support structure 210 include ceramics and metals structures surrounded by ceramics.

Each of air supply channel 212 and air supply channel 214 may be any system or structure that transfers air from air preheating chamber 220 to primary burn chamber 204 and secondary burn chamber 206.

Supply air intake 216 may be any system or structure that provides external air to air preheating chamber 220.

Airwash intake 218 may be any system or structure that provides external air towards primary burn chamber window 226 and towards secondary burn chamber window 230.

Air preheating chamber 220 may be any system or structure that is able to provide pre-heated air to primary burn chamber 204 and to each o air supply channels 212 and 214.

Cooling chamber 222 may be any system or structure that is able to provide heated air from second burn chamber 206 to gas flow controller 208 in a down-draft mode of operation. Cooling chamber 222 is additionally able to transfer heat from air preheating chamber 220 to the air outside of down-draft heating device 100. In this manner, the air provided to gas flow controller 208 has a minimized temperature and the amount of heat transferred to the outside air is maximized.

Each of exhaust manifold 213 and exhaust manifold 215 may be any system or structure that transfers air from secondary hum chamber 206 to cooling chamber 222.

Primary burn chamber door 224 may be any system or structure that enables access to primary burn chamber 204 so as to load solid fuel onto solid fuel support structure and to clean/service primary burn chamber 204. Primary burn chamber window 226 may be any system or structure that enables a sealed viewing into primary burn chamber 204.

Secondary burn chamber door 228 may be any system or structure that enables access to secondary burn chamber 206 so as to clean/service secondary burn chamber 206. Secondary burn chamber window 230 may be any system or structure that enables a sealed viewing into secondary burn chamber 206.

The structure of a non-limiting example of a down-draft heating device in accordance with aspects of the present invention will now be described with reference to FIGS. 3-10.

FIG. 3 illustrates an example heating device bottom 300 of an example down-draft heating device in accordance with aspects of the present invention.

As shown in the figure, heating device bottom 300 includes a panel 302, a support structure 304, a support structure 306 and a control shuttle 308. Panel 302 includes a portion 310 and a portion 312. Portion 310 has an air supply port 314. Portion 312 has an airwash air supply port 316, an extended portion 318 and an extended portion 320.

Panel 302, support structure 304, support structure 306 and control shuttle 308 may be made of any material that can withstand temperatures created by a down-draft heating device in accordance with aspects of the present invention, non-limiting examples of which include metals, ceramics and combinations thereof.

Air supply port 314 enables external air to enter into the down-draft heating device so as to be used in the primary and secondary burn chambers. Airwash supply port 316 enables external air to enter into the down-draft heating device so as to be used to provide airwash to the primary burn chamber window and the secondary burn chamber window.

Support structure 306 separates external air supplied by air supply port 314 from external air supplied by airwash supply port 316. Support structure 304 and support structure 306 additionally provide support for a top panel, as will be described with reference to FIG. 4.

FIG. 4 illustrates an example air input chamber 400 of an example down-draft heating device in accordance with aspects of the present invention.

As shown in the figure, air input chamber 400 includes heating device bottom 300 and a panel 402. Panel 402 has an air supply port 404. Further, panel 402 is positioned on heating device bottom 300 so as to provide an airwash channel 406.

Panel 402 may be made of any material that can withstand higher temperatures created by the secondary burn chamber, non-limiting examples of which include metals, ceramics and combinations thereof. In some embodiments, panel 402, panel 302, support structure 304, support structure 306 and control shuttle 308 are made of the same material. In other embodiments, panel 402 is made of a material different than that of panel 302, such that panel 402 can withstand higher temperatures than panel 302.

Portion 310 of heating device bottom 300 forms a chamber with the outer walls of the heating device (not shown) and support structure 306. In this manner, any external air entering air supply port 314 will only be able to escape through air supply port 404. Further, this chamber, the height of which is the distance between panel 302 and panel 402 as created by support structures 304 and 306, creates a thermal buffer from the high heat generated in the second burn chamber from the underside of the down-draft heating device. In this manner, flooring below the down-draft heating device will not be damaged by excessive heat.

Separating air supply port 314 from air supply port 404 by a distance d prevents any flames or debris from passing From the secondary burn chamber or the primary burn chamber through air input, chamber 400 so as to exit the down-draft heating device.

Panel 402 extends beyond support structure 306 so as to create a channel that enables external air entering airwash supply port 316 to be directed toward extended portions 318 and 320, as will be described in greater detail later.

FIG. 5 illustrates an oblique view of the example air input chamber of FIG. 4 in addition to a rear portion.

As shown in the figure, the rear portion includes a preheating, chamber rear panel 500 and a cooling chamber rear panel 502. Cooling chamber rear panel 502 is separated from preheating chamber rear panel 500 by a cooling chamber 504.

FIG. 6 illustrates an oblique view of a more completed down-draft heating device of FIG. 5.

As shown in FIG. 6, a preheating chamber 600 includes a preheating chamber front and 602, a preheating chamber side panel 604 and a preheating chamber top panel 606. Another preheating chamber side panel opposite to preheating chamber side panel 604 is not shown. Preheating chamber from. panel 602 includes an air supply port 608, an air supply port 618 and an air supply port 620 Preheating chamber top panel 606 includes an alternate exhaust port 610. Additionally included in the figure are a ceramic support 612 and a ceramic support 614, separated by a distance 616.

Ceramic support 612, ceramic support 614 and preheating chamber front panel 602 may be made of any material that can withstand higher temperatures created by the secondary burn chamber, In some embodiments, preheating chamber front panel 602, both preheating chamber side panels including preheating chamber side panel 604 and preheating chamber top panel 606 are made of the same material. In other embodiments preheating chamber from panel 602 is made of a material different than that of both preheating chamber side panels including preheating chamber side panel 604 and preheating chamber top panel 606, such that panel 602 can withstand higher temperatures than both preheating chamber side panels including preheating chamber side panel 604 and preheating chamber top panel 606.

Ceramic support 612 and ceramic support 614 are separated from one another by an area 616. Further, ceramic support 612 and ceramic support 614 are removable, and may therefore be replaced if they become damaged or they deteriorate from use.

In this example embodiment, air supply port 608 takes the form of a plurality of holes in preheating chamber front panel 602. External air supplied by air supply port 314 will exit u/down-draft air supply port 404 into preheating chamber 606, and will then exit from air supply port 608.

Gases that are behind preheating chamber 600 in cooling chamber 504 will exit through down-draft exhaust port 610.

FIG. 7 illustrates an oblique view of a more competed down-draft heating device of FIG. 6.

As shown in FIG. 7, a solid fuel support structure 700 includes a plurality of ceramic bricks 702 a sample of which are labeled as ceramic brick 704 and ceramic brick 706, ceramic support 612 and ceramic support 614. Solid fuel support structure 700 forms around a secondary burn chamber 708. Solid fuel support structure 700 includes a plurality of airways, a sample of which is indicated as a slot 710.

Solid fuel support structure 700 may be made of any material that can withstand higher temperatures created by secondary burn chamber 708. In this example embodiment, the plurality of airways in solid fuel support structure 700 includes a plurality of slots. It should he noted that these slots are a non-limiting example. Any type of airway may be provided in accordance with aspects of the present inventions, so long as air, gases and particulates can pass through solid fuel support structure to secondary burn chamber 708,

Solid fuel support structure 700 is removable, such that it may be replaced if it becomes damaged or it deteriorates from use.

FIG. 8 illustrates an oblique view of a more competed down-draft heating device of FIG. 7.

As shown in FIG. 8, solid fuel support structure 700, a sidewall 802, a sidewall 804 and a front fuel support structure 806 form a primary burn chamber 808. Further, an air supply chamber 810 having an end cap 812 is adjacent to ceramic support 612, whereas an air supply chamber 814 having an end cap 816 is adjacent to ceramic support 614. A space between air supply chamber 810 and an outer wall (not shown) is an exhaust manifold 818, whereas a space between air supply chamber 814 and an outer wall (not shown) is an exhaust manifold 820.

Sidewall 804, sidewall 802, air supply chamber 810 and air supply chamber 814 may be made of any material that can withstand temperatures created within primary burn chamber 808. Front fuel support structure 806 may be made from any material that can withstand temperatures created within secondary burn chamber 708.

Fuel support structure 806 prevents airflow from secondary burn chamber 708 to primary burn chamber 808, and vice versa. Air supply chamber 814 supplies an into secondary burn chamber 708 from preheating chamber 600 through air supply port 620. Air supply chamber 812 similarly supplies air to secondary burn chamber 708 from preheating chamber 600 through air supply port 618 (as shown in FIG. 6).

Exhaust manifold 818 steers a portion of heated gasses from secondary burn chamber 708 to cooling chamber 504 behind preheating chamber 600. Similarly, exhaust manifold 820 steers a portion of heated gasses from secondary burn chamber 708 to cooling chamber 504 behind preheating chamber 600. Heat is extracted from the heated gasses as they pass through exhaust manifold 818 and 820 and is conducted to the outer wails of the down-draft heating device. The heat then conducts to the external air around the down-draft heating device.

FIG. 9 illustrates an oblique view of a more competed down-draft heating device of FIG. 8.

As shown in FIG. 9, an outer housing 902 is supported by legs, a sample of which is labeled as leg 904. A gas flow controller 906 includes a handle 908. An airwash channel 912, a primary burn chamber window airwash channel 914, an opening 916 for primary burn chamber 806 and an opening 918 for secondary burn chamber 708 are located at the front of the down-draft heating device. An up-draft exhaust part 920 is located under gas flow controller 906.

Secondary burn chamber window airwash channel 912 has holes directed toward opening 914. Primary burn chamber window airwash channel 914 has holes directed toward opening 912.

Gas flow controller 906 is any system that enables switching between an up-draft mode and a down-draft mode: wherein in the up-draft mode, an up-draft exhaust port 920 is uncovered, while down-draft exhaust port 610 is covered, and wherein in the down-draft mode, up-draft exhaust port 920 is covered, while down-draft exhaust port 610 is uncovered. When up-draft exhaust port 920 is covered, air and gases are prevented from flowing from primary burn chamber 808. When up-draft exhaust port 920 is uncovered, air and gases flow from primary burn chamber 808.

FIG. 10 illustrates an oblique view of a complete down-draft heating device 1000 in accordance with aspects of the present invention.

As shown in the figure, down-draft heating device 1000 includes a top panel 1002, an exhaust stack 1004, a primary burn chamber door 1006, a primary burn chamber window 1008, a handle 1010, a secondary burn chamber door 1012, a secondary burn chamber window 1014, a handle 1016 and corner channels (such as corner channel 1018).

Top panel 102 creates a chamber to force air/gases to exit through exhaust stack 1004. In an up-draft mode, when up-draft exhaust port 920 (as shown in FIG. 9) is uncovered and when down-draft exhaust port 610 (as shown in FIG. 6) is covered, air and gases flow from primary burn chamber 808 to exit through exhaust stack 1004. In a down-draft mode, when up-draft exhaust port 920 as shown in FIG. 9) is covered and when down-draft exhaust port 610 (as shown in FIG. 6) is uncovered, air and gases flow from secondary burn chamber 708, through down-draft exhaust port 610 to exit through exhaust stack 1004. Corner channels, such as corner channel 1018 direct airwash supply to secondary burn chamber window airwash channel 912 and primary burn chamber window airwash channel 914 of FIG. 9,

Primary burn chamber door 1006 may be may be made of any material that can withstand temperatures created by primary burn chamber 808. Primary burn chamber window 1008 may be any transparent material that can withstand temperatures created by primary burn chamber 808. Primary burn chamber door 1006 is openable/closeable. In this example embodiment, handle 1010 is used to open/close primary burn chamber door 1006. When opened, primary burn chamber door 1006 enables access to primary burn chamber 808.

Secondary burn chamber door 1012 may be may be made of any material that can withstand higher temperatures created by secondary burn chamber 708. Secondary burn chamber window 1014 may be any transparent material that can withstand higher temperatures created by secondary burn chamber 708. Secondary burn chamber door 1012 is openable/closeable. In this example embodiment, handle 1016 is used to open/close secondary burn chamber door 1012. When opened, secondary burn chamber door 1012 enables access to secondary burn chamber 708.

Down-draft heating device 1000 is initially operated in an up-draft mode. Once the temperature is sufficiently high and sufficient hot coals have developed within primary burn chamber 808, down-draft heating device 1000 may be operated in the down-draft mode.

The up-draft mode of operation of down-draft heating device 1000 in accordance with aspects of the present invention will now be described with reference to FIGS. 11-16.

FIG. 11 illustrates air flowing in and gas flowing out of down-draft heating device 1000 during an up-draft mode of operation.

As shown in FIG. 11, external air 1102 and external air 1104 is supplied to down-draft heating device 1000, which additionally outputs exhaust 11.06 from exhaust stack 1004.

In the up-draft mode, solid fuel, such as for example wood, is supplied to primary burn chamber 808, as shown in FIG. 8, through primary burn chamber door 1006, as shown in FIG. 10. The solid fuel is deposited on solid fuel support structure 700, as shown in FIG. 7.

External supply air, such as that indicated by arrows 1102 and 1104 is supplied, to primary burn chamber 808, such that when the solid fuel is ignited, it burns. The burning fuel heats air in primary burn chamber 808 and heated air and gases escape as exhaust 1106 though exhaust stack 1004. Air being supplied to primary burn chamber starts at heating device bottom 300. This will be described in greater detail with reference to FIGS. 12-13.

FIG. 12 illustrates air flow through heating device bottom 300.

As shown in the figure, supply air 1202 is provided through air supply port 314 and an airwash supply 1204 is provided through airwash supply port 316.

FIG. 13 illustrates air flow through the heating device air input chamber of FIG. 4.

As shown in the figure, supply air 1302 is provided through air supply port 404 and airwash supply 1204 is provided through airwash supply port 316.

Supply air 1302 is pulled through air supply port 404 as a result of being heated by primary burn chamber 808 and as a result of the gases leaving exiting primary burn chamber 808. Supply air 1302 is pulled from air supply port 314 as shown by supply air 1202. The air between panel 402 and panel 302, e.g., supply air 1202 provides an important function it acts as a thermal barrier preventing excessive heat from damaging the floor under down-draft heating device 1000.

FIG. 14 illustrates air flowing in through the heating device bottom of FIG. 6.

As shown in FIG. 14, a portion of supply air flow 1402 is supplied by air supply port 620 and another portion of supply air flow 1404 is supplied by air supply port 618. Portion of supply air flow 1402 flows through gas vias 622 of ceramic support 614 into secondary burn chamber 708 as supply air 1406 Similarly, portion of supply air flow 1404 flows through gas vias 624 of ceramic support 612 into secondary burn chamber 708 as supply air 1408.

The supply air flows from gas vias 622 and 624 combine to provide an supply air flow 1410 to plurality of ceramic bricks 702 that are supporting the burning solid fuel. This will be described in greater detail with reference to FIG. 15.

FIG. 15 illustrates gas flow in the primary burn chamber as shown in FIG. 8.

As shown in FIG. 15, supply air 1302 is pulled through preheating chamber 600 and exits air supply port 608 to primary burn chamber 806 as supply air 1502. Additionally, supply air flow 1410 is provided to primary burn chamber 806 through the slots, such as slot 710, of the plurality of ceramic bricks 702 of solid fuel support structure 700. Supply air flow 1410 and supply air 1502 provides oxygen to burn solid fuel 1504, thus creating fire 1506, which creates a heated up-draft 1508.

FIG. 16 illustrates gas flow in an up-draft operation of the down-draft heating device as shown in FIG. 9.

As shown in FIG. 16, up-draft exhaust port 920 emits an exhaust 1602, whereas a down-draft exhaust port 1604 is covered. Heated air and gasses from fire 1506 form exhaust 1602. Exhaust 1602, rising through up-draft exhaust port 920, pulls more air 1502 (as shown in FIG. 15), which pulls more supply air 1302, which pulls more supply air 1202 (as shown in FIG. 13), which pulls more external air (as shown in FIG. 11).

Airwash supply 1204 splits to flow to both sides of the front of the heating device. Each portion of the split airwash supply 1204 flows up a respective corner channel (for example corner channel 1018) on each side of the from of the heating device. A portion of airwash supply 1204 at each side then flows along secondary burn chamber window airwash channel 912, whereas the remainder of airwash supply at each side then flows along primary burn chamber window airwash channel 914.

Holes or perforations in secondary burn chamber window airwash channel 912 create a secondary burn chamber window airwash 1606, which prevents particulates and creosote from secondary burn chamber 708 from striking and sticking or congealing to secondary burn chamber window 1014. Therefore, secondary burn chamber window airwash 1606 keeps secondary burn chamber window 1014 clean.

Similarly, holes or perforations in primary burn chamber window airwash Channel 914 create a primary burn chamber window airwash 1608, which prevents particulates from primary burn chamber 808 for striking and sticking to primary burn chamber window 1008. Therefore, primary burn chamber window airwash 1608 keeps primary burn chamber window 1008 clean.

While in the up-draft mode, the burning fuel heats air in primary burn chamber 808. Some of the heat from the heated air is transferred to plurality of ceramic bricks 702 (as shown in FIG. 7), side wall 802 and side wall 804 (as shown in FIG. 8), gas flow controller 906 (as shown in FIG. 9), primary burn chamber door 1006 and primary burn chamber window 1008 (as shown in FIG. 10).

A portion of the heat transferred to plurality of ceramic bricks 702 eventually finds its way, through conduction between the touching metal/ceramic, parts, to the air outside of down-draft heating device 1000. The heat transferred to side wall 802 and side wall 804 conducts to outer housing 902, which then conducts to the air outside of down-draft heating device 1000. The heat transferred to gas flow controller 906 eventually finds its way, through convection and conduction, to top panel 1002 (as shown in FIG. 10), which then conducts to the air outside of down-draft heating device 1000. The heat transferred to primary burn chamber door 1006 and primary burn chamber window 1008 (as shown in FIG. 10) conducts and radiates directly to the air and area outside of down-draft heating device 1000. However, a part of the heat created from the burning fuel remains in the heated air and eases that are exhausted through exhaust stack 1004, as with most conventional solid fuel burning heating devices.

Furthermore, the conventional temperatures associated with the up-draft mode when burning solid fuel result in many relatively large quantity of particulates in the gases. As such, the exhaust through exhaust stack 1004 is particularly “dirty.” On the contrary, a down-draft mode burns at a much higher temperature, which incinerates much of the particulates that would have been otherwise generated in the up-draft mode. Further, in accordance with aspects of the present invention, much more heat is transferred to outside of down-draft heating, device 1000 in the down-draft mode before the heated air and gases are exhausted through exhaust stack 1004.

After down-draft heating device 1000 has operated in the up-draft mode to sufficiently raise the temperature of the air within cooling chamber 504, such that when down-draft exhaust port 1604 is opened, the heated air within cooling chamber 504 escapes and creates sufficient suction together with the buoyancy of the hot air in the exhaust stack (not shown) so as to pull sufficient external air through the bottom of down-draft heating device to force a down-draft through solid fuel support structure, down-draft heating device 1000 may be operated in a down-draft mode. To switch to the down draft mode, gas flow controller 906 (as shown in FIG. 9) should be actuated so as to cover up-draft exhaust port 920 and so as to uncover down-draft exhaust port 1604 (as shown in FIG. 16).

The down-draft mode of operation of down-draft heating device 1000 in accordance with aspects of the present invention will now be described with reference to FIGS. 11-14 and 17-19.

FIG. 17 illustrates gas flow in a down-draft operation of the down-draft beating device as shown in FIG. 9.

As shown in FIG. 17, down-draft exhaust port 1604 emits an exhaust 1700, whereas up-draft exhaust port 920 is covered. A more detailed explanation of operation of the down-draft mode will be provided with additional reference to FIG. 18.

FIG. 18 illustrates gas flow in a down-draft operation of the down-draft heating device as shown in FIG. 8.

FIG. 18 includes arrows illustrating the flow of a down-draft 1802, supply air 1406, supply air 1408, supply air 1804, exhaust gases 1806, exhaust gases 1808, exhaust gases 1810 and exhaust gases 1812.

When up-draft exhaust port 920 is covered by gas flow controller 906 as shown in FIG. 17, there is nowhere for the heated gas to escape except for down-draft exhaust port 1604. As shown in FIG. 18, secondary exhaust 1700 escapes down-draft exhaust port 1604, which pulls exhaust gases 1812 up through cooling chamber 504, behind preheating chamber 600. The flow of exhaust gases 1812 pulls exhaust gases 1810 alongside of air supply chamber 814. A similar flow of exhaust gases pass along side of air supply chamber 810 on the other side.

The flow of exhaust gases 1810 pulls exhaust gases 1808 from secondary burn chamber 708. A similar flow of exhaust gases 1806 are pulled from secondary burn chamber 708 to the opposite side. The flow of exhaust gases 1806 and 1808 pull air and gases down from primary burn chamber 808, around and through the burning solid fuel, through the slots of solid fuel support structure 700 as a down-draft 1802 into secondary burn chamber 708. Further, flow of exhaust gases 1806 and 1808 pulls supply air 1406 through gas vias 622 and pulls supply air 1408 through gas vias 624. The constant flow of supply air 1402 in air supply chamber 814 extracts heat from ceramic support 614. This heat extraction essentially cools ceramic support 614, thus reducing the likelihood of thermal damage or deterioration. This heat extraction additionally prevents thermal damage or deterioration to the surfaces of air supply chamber 814. The constant flow of supply air 1404 in air supply chamber 810 provides a similar benefit to ceramic support 612 and to the surface of air supply chamber 810.

Down-draft 1802 pulls more air and gases from air supply port 608 as supply air 1804. This will be described in greater detail with reference to FIG. 19.

FIG. 19 illustrates down-draft air flow in through the heating device bottom of FIG. 6.

FIG. 19, includes down-draft 1802, supply air flow 1402, supply air flow 1404, supply air 1406 and supply air 1408.

Down-draft 1802 passes through the slots in plurality of ceramic bricks 702 and into secondary burn chamber 708. When down-draft 1802 passes through the burning solid fuel 1504, the gases and particulates are exposed to tremendous heat, which causes a second burn. Supply an 1406 and supply air 1408 provide oxygen for the second burn. This second burn breaks down most of the remaining the particulates thus reducing the amount of particulates in the resulting gases.

A down-draft heating device in a down-draft mode in accordance with aspects of the present invention, generates more heat in a more efficient manner than conventional up draft heating devices and further does not overheat so as to damage, degrade or destroy parts of the down-draft heating device. This will now be further described in greater detail.

When down-draft 1802 passes through the burning fuel and through solid fuel support structure, its temperature is drastically increased. For example, for a normal up-draft wood burning burn chamber, the temperature may be in the range of (800-1200° F.). Whereas for down-draft heating device 1000 burning wood, the temperature in secondary burn chamber 708 may be in the range of (1600-2000° F.). This drastically increased temperature incinerates much more solid fuel, thereby leaving much less particulates in the heated air and gases in secondary burn chamber 708. In essence, down-draft 1802 is a “re-burn,” wherein gases and particulates from a previous burn are burned again, which drastically reduces the number and size of particulates.

Because of the dramatically increased temperatures in secondary burn chamber 708, all surfaces exposed to secondary burn chamber 708 should he of a very heat resistive material, non-limiting examples of which include heat resistive ceramics. Further, combinations of ceramics and metals may be used.

Returning to FIG. 7, the surfaces of solid fuel support structure 700 that are in contact with secondary burn chamber 708 will bear the brunt of the extreme heat while in the down-draft mode. The adjacent chambers having air passing through will act as heat sinks, pulling this extreme heat from solid fuel support structure 700, thus preventing overheating, and thus preventing damage, degradation or destruction of solid fuel support structure 700.

From below, returning, to FIG. 13, panel 402 acts as a heat sink to absorb a portion of the heat created in secondary burn chamber 708 namely at the bottom surface. The relatively cool externally fed air, which is constantly flowing between panel 402 and heating device bottom 300 from air supply port 314, draws heat from heated panel 402 until it exits air supply port 404 as supply air 1302. The air between panel 302 (as shown in FIG. 3) and panel 402 (as shown in FIG. 4 acts as a thermal barrier, protecting the flooring under down-draft heating device 1000 from excessive heat.

Therefore, the arrangement of chambers, and flowing gasses transfers heat at the rear of secondary burn chamber 708 from solid fuel support structure to outside of down-draft heating device 1000. This heat transfer both increases the heating efficiency down-draft heating device 1000 to heat the surrounding area and preventing damage, degradation or destruction of areas around secondary burn chamber 708.

From the sides, returning to FIG. 68 air supply chamber 814 acts as a heat sink to absorb heat from ceramic support 614 and from the plurality of ceramic bricks 702 (as shown in FIG. 7).

Therefore, the arrangement of chambers, and flowing gasses transfers heat at the rear of secondary burn chamber 708 from solid fuel support structure to outside of down-draft heating device 1000. This heat transfer both increases the beating efficiency of down-draft heating device 1000 to heat the surrounding area and preventing damage, degradation or destruction of areas around secondary burn chamber 708.

From the side, the heat absorbed by ceramic support 612 (as shown in FIG. 6) will conduct to air supply chamber 810 (as shown in FIG. 8). Similarly, the heat absorbed by plurality of ceramic bricks 702 (as shown in FIG. 2) will conduct to air supply chamber 814 (as shown in FIG. 8).

Heat from exhaust gases 1806, 1810 and 1810 will be transferred to outer housing 902, as shown in FIG. 9, which then conducts this heat to the air outside of down-draft heating device 1000.

It should be noted that a similar transfer of heat from secondary burn chamber 708 to the air outside of down-draft heating device 1000 occurs on the other side corresponding to ceramic support 612 and air supply chamber 814.

From the front, as shown in FIG. 18, airwash supply 1204 assists the redirection of air and gasses escaping secondary burn chamber 708 away from secondary burn chamber door 1012 and secondary burn chamber window 1014. Sonic of the heat from secondary burn chamber 708 is conducted through airwash supply 1204 secondary burn chamber door 1012 and secondary burn chamber window 1014, which then conducts and radiates this heat to the air outside of down-draft heating device 1000. Glass is a particularly good heat sink. When glass is used for secondary burn chamber window 1014, much heat conducts and radiates to the outside air and area. Along these lines, airwash supply 1204 additionally prevents particulates and creosote from secondary burn chamber 708 from sticking to secondary burn chamber window 1014, thus keeps secondary burn chamber window 1014 clean.

The thermal transfer efficiency of a down-draft heating device in accordance with aspects of the present invention may be improved with the addition of tins or protrusions along surfaces for which heated air and gasses pass, non-limiting examples of which include: the inner surfaces of air supply chamber 810 and 814; the inner surfaces of preheating chamber 600; the surfaces surrounding cooling chamber 504; the surfaces between air supply chamber 810 and outer housing 902; and the surfaces between air supply chamber 814 and outer housing 902, and combinations thereof.

With respect to cleaner air, it should be noted that as the circulating heated air and gases within down-draft heating device 1000 cools, that it transfers heat to outer housing 902 and thus the outside air, some particulates and. ash drop out to the bottom of down-draft heating device 1000. For example, particulates within exhaust. gases 1808, 1810 and 1812 as shown in FIG. 18 will fall to the top of air input chamber 400. These particulates and ash may be cleaned when down-draft heating device 1000 cools by way of secondary burn chamber door 1012.

Conventional solid fuel up-draft heating devices are limited in the amount of heat they can generate and further produce relatively large amounts of pollution in the form of particulates. A conventional solid fuel down-draft heating device burns much hotter, which reduces pollution over that of conventional solid fuel up-draft heating devices. However, conventional solid fuel down-draft heating devices succumb to thermal degradation and destruction as a result of the extreme temperatures from the secondary burn. Further, some conventional solid fuel down-draft beating devices have a single door to access the primary burn area and the secondary burn area.

In accordance with aspects of the present invention, a down-draft heating device includes a secondary burn chamber having surfaces made of high temperature resistive materials to prevent thermal degradation and destruction. Further, a plurality of chambers wick heat from the surfaces of the secondary hum chamber to the outer surfaces of the down-draft heating device. These chambers therefore increase the efficiency of the down-draft heating device for transferring beat to the outside air.

In the drawings and specification, there have been disclosed embodiments of the invention and, although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being set forth in the following claims. 

What is claimed as new and desired to be protected by Letters Patent of the United States is:
 1. A heating device comprising; a primary burn chamber; a secondary burn chamber; a solid fuel support structure separating said primary burn chamber and said secondary burn chamber, said solid fuel support structure being operable to support a solid fuel for burning in said primary burn chamber, to pass air from said secondary burn chamber to said primary burn chamber and to pass gas and particulates from said primary burn chamber to said secondary burn chamber; an exhaust port operable to exhaust gases; a cooling chamber disposed between said secondary burn chamber and said exhaust port, said cooling chamber bung operable to extract heat from gases from said secondary burn chamber; an first port operable to supply external air to said primary burn chamber; a second port operable to supply external air to said secondary burn chamber; and a gas flow controller operable to block said exhaust port in a downdraft mode thus preventing exhaust gases from exhausting, through said exhaust port and operable to unblock said exhaust port in a updraft mode such that exhaust gases exhaust through said exhaust port.
 2. The heating device of claim 1, wherein said solid fuel support structure comprises one of the group consisting of a grate, a mesh, a slotted-structure, a screen and combinations thereof.
 3. The heating device of claim 1, further comprising: a primary burn chamber window covering said primary burn chamber; and a secondary burn chamber window covering said secondary burn chamber.
 4. The heating device of claim 3, wherein said primary burn chamber window is openable, and wherein said secondary burn chamber window is openable.
 5. The heating device of claim 1, wherein said gas flow controller comprise a rod and a baffle.
 6. The heating device of claim 1, wherein said secondary burn chamber comprises a first ceramic material, and wherein said solid fuel support structure comprises a second ceramic material.
 7. The heating device of claim 6, wherein said secondary burn chamber additionally comprises a first metal, and wherein said first metal of said secondary burn chamber is partially surrounded by said first ceramic material.
 8. The heating device of claim 1, further comprising; a first exhaust manifold operable to extract heat from a first portion of gasses passing from said secondary burn chamber to said cooling chamber; and a second exhaust manifold operable to extract heat from a second portion of gasses passing from said secondary burn chamber to said cooling chamber, wherein said secondary burn chamber is disposed between said first exhaust manifold and said second exhaust manifold.
 9. The heating device of claim 8, wherein said first exhaust manifold comprises a structure having an gas path leading from said secondary burn chamber to said cooling chamber and a plurality of heat sink protrusions protruding into said gas path.
 10. The heating device of claim 1, wherein said solid fuel support structure is disposed between said first port and said second port.
 11. The heating device of claim 1, wherein said first port comprises a plurality of holes. 